Incidence of Acute Mountain Sickness in Adolescents Backpacking at Philmont Scout Ranch.

Introduction: Individuals ascending to elevations above 2500 m are at risk of developing altitude illness. We sought to establish the incidence and to determine what risk factors, if any, increased the likelihood of developing acute mountain sickness (AMS) in adolescents at Philmont Scout Ranch (PSR) in Cimarron, New Mexico. PSR, with elevations ranging from 2011 to 3792 m, attracts thousands of adolescent participants each year, many of whom arrive from lower elevations with little or no experience ascending to high altitude.

Methods: We conducted a prospective observational study of adolescent participants aged 14 to 19 years who ascended to a minimum of 3000 m while trekking from June to July 2021. Prior to the start of each participant's trek, pretrek survey data were obtained at PSR's basecamp (2011 m). During the trek at 3048 m, the Lake Louise AMS score was used to diagnose AMS.

Results: The incidence of AMS in our study was 13.7%. Participants reporting a history of daily headaches had more than four times the risk of developing AMS. A history of gastrointestinal problems carried three times the risk of developing AMS, and a prior history of AMS increased the risk of developing AMS by 44%.

Conclusions: Our findings enhance our understanding of AMS risk in adolescents and may provide guidance to youth for developing AMS. For individuals with a history of headaches or gastrointestinal problems or a prior history of AMS, there may be an opportunity to reduce the risk of developing AMS.